Error trying to save custom footprint


#21

@sg.giffin I also forgot to mention that different manufacturers (and even different processes from the same manufacturer, e.g. prototype vs production) may have different tolerances and THT wall build-ups. Rene has the better idea of first contacting your board vendor with the part datasheet on hand. If you are lucky, you might be able to get them to throw your test board “coupon” into an unused area of another customer’s panel and provide you the coupons for next to (or actually) nothing plus shipping.


#22

Thank you for this information. Is there a way to specify THT tinning thickness in kicad?


#23

Not that I know of. That is why you need to contact the PCB vendor that you plan on using. I don’t know much about THT wall thickness other than it is a measurable, and to some point a controllable, property of the boards. For all I know, the wall thickness specified in the part’s datasheet is close to what PCB vendors do nominally. Or, it could be a completely custom thickness that requires tight communication with the vendor.


#24

Normally the drill diameter is the finished hole diameter. So there is not really a need to know (for the designer) how thick the plating is.


#25

The current practice is to specify the FINISHED hole size on your drawings (footprints, Gerbers, drill files, etc). A vendor who asks you for the drill size before plating is 20 years (or more) behind the times. I discussed this in old posts at, e.g., " Drill Hole Sizes " and " PCB Designing for 6 Layer ".

When specifying a hole pattern for press-fit, remember that there are several tolerance factors at work. Of course there is the tolerance on the hole diameter itself. For quick-turn, prototype, and short-run boards this reflects not only a basic, fundamental, machining tolerance but also a tolerance based on how your requested hole size (e.g., 0.0625") gets mapped into the sizes available from the vendor’s “standard tool rack” (where the closest sizes may be 0.060" and 0.067"). And there is also a tolerance on the position of the hole center. The most comprehensive document dealing with these factors is SEEED Studio’s " PCB Design for Manufacturing " manual (paper copy at " SEEED Design Guidlines ").

As others have said, you need to contact the PCB fabricator if your tolerance requirements are tighter than the vendor’s published values.

Dale